Apparatus for finishing reflector blanks



Feb. 9,1926. 1,572,451

. W. H. TAYLOR APPARATUS FOR FINISHING REFLECTOR BLANKS Filed June 5, 1922 IN VE/VTOR Zmuy 7 v Patented Feb. 9, 1926.

UNITED STATES A 1,572,451 PATENT OFFICE.

WILLIAM H. TAYLOR, OF FORD CITY, PENNSYLVANIA, ASSIGNO-R ITO PITTSBURGH PLATE GLASS COMPANY, A CORPORATION OF PENNSYLVANIA.

APPARATUS FOR FINISHING REFLECTOR IBLANKS.

Application filed June 5, 1922. Serial No. 566,292.

and State of Pennsylvania, have made a new and useful Invention in Improvements in Apparatus for Finishing Reflector Blanks,

of whlch the following is a specification.

The invention relates to apparatus for finishing the glass reflector blanks and particularly the large sizes employed running up to sixty inches or more 1n diameter. These blanks have the usual sharp corners incident to cuttitng the blank to circular form preliminary to bending and it becomes necessary to finish these edges by beveling off the corners and smoothing and truing up' the edges so that the glass has a uniform diameter throughout. In some cases the finishing operation also calls for the cutting of a hole several inches in diameter centrally of the reflector. The invention has for its principal objects the provision of improved means for accomplishing the .above operations simultaneously, at a small expense and without danger of breaking or chipping the glass. It will be understood that while the apparatus is designed primarily for use upon large reflector blanks, the invention is not limited to use in such connection, and that it comprehnds all uses of the apparatus as a whole or in part where similar functions are accomplished. One embodiment of the invention is illustrated in the accompanying drawings wherein:

Figure 1 is a vertical section through the apparatus with the parts in position of use; Fig. 2 is an enlarged detailed section through the device for cutting the opening through the central portion of the glass blank; Fig. 3 is a plan view of the appara-' tus ona reduced scale to show the relative location of the three edge finishing discs or wheels; Fig. 4 is an enlarged section on, the

line IVIV of Fig. 3; and Fig 5 is an en larged section through'the lower edge of the blank after the edge hasbeen finished by the three sets of grinding wheels.

Referring to Fig. 1, the glass blank 1 which is to be finished is carried by the table or support, 2, to which it is secured by'a layer 3 of adhesive material, such as itch,-

which holds the lass-ver securely a er it has hardened. e tab e is rotated by means of the axle or shaf yhavinga suitable thrust bearing 5, at its lower end and a pair of other bearings 6-and 7 carried upon the framework 8. Intermediate the two bearings 6 and 7 is a pulley 9 which is keyed to the shaft and driven from the belt 10.

Carried by the framework 8 and spaced around the periphery of the table atsubstantially equal distances are the brackets 11, 12 and 13 which act as supports forthcthree grinding wheels 14, 15 and16. The grinding wheels are made of suitable abrasive or cutting material, such as stone or OOIIIIJOSItlOIl, and are designed to cut the three surfaces 17 18 and 19, shown on an enlarged scale in Fig. 5, the Wheel 14 cutting the bevel 17, the wheel 15, the bevel 18 and the wheel 16 the surface 19. As will be seen by reference to Figs. 1 and 4, the wheels and their supportin means are of similar construction, the onfi difference being that they lie at different angles with'respect to the edge of the blank in order to cut the three difierent surfaces. A detailed description, therefore, of one will be suflicient to indicate "the construction of the other two. Using the wheel 14 for the purpose of this description, this wheel is mounted upon an axis 221 The wheel is normally pressed forward, so that its face engages the edge of the glass by means of the spring 23 whose 1 tension may be adjusted by means of the threaded member 23? extending through the 1 lower end of the arm 21. l The forward movement of the arm 21 is limitedby means .of the screw member 24 which is threaded through the armand is. ada ted to engage the projection 25 on the brac et 11 after the essary to'cut the bevel 17. v

The center line 26 of the wheel 14*is 10-. cated off 'center with respect to the point of contact 27 between the edge of the. glass blank and the wheel so that the rotation of arm has been fed forward the distancened.

the glassblank causes a rotation of the grinding wheel. The distance which the center llne 26 is ofl" center'with respect to the line of grindin contact is relatively slight, :however, so t la't'the rotation of the wheel 14 is quite slow. The other grinding wheels 15 and 16 are similarly mounted upon arms 28. and 29 and the relation of the arm being pivoted to the bracket'll upon the 1 wheels to the line of grinding contact is similar to that above set forthwith respect to the wheel 14. The use of the s rings 23 serves to give the necessary grin ing. contact between the wheels and the edge of the blank, which grinding pressure is heaviest at the beginning of the operation and gradually decreases as the grinding progresses, the extent of grinding being determined by the adjustable stop devices 24.. The decreasing pressure as the grindingprogresses is advantageous as the decreased pressure gives a finer grinding finish and the surface pro duced is better than if the same relatively high grinding pressure were maintained throughout the operation. V

In order to cut the opening through the center of the glass while the edge finishing operation is in progress, the cutting cylinder 30, shown in detail in Fig. 2, is em ployed. This cylinder is carried by a transverse' bar 31 upon which the device is sup ported by means of the spindle 32. The cylinder 30 is preferably of co per and is bolted to a cast iron ring 33 w ich is provided at its center with the ball socket 34 adapted to receive the ball 35 at the lower end of the spindle 32, the screw sleeve 36 serves to hold the ball in position in the socket.- The spindle 32 slides freely in a, vertical direction through the boss '37 carried by the bar 31, but is preventedfrom rotating by means of the key 38. In order to prevent the rotation 'of the cylinder 30, the interengaging pins 39 and 40 are employed,'the in 39 being secured in the spindle 32 and t e pin v40 being secured in the ring member 33.

In order to make the lower edge of the copper cylinder 30 effective as-a glass cutter, such edge is charged with a hard abrasive powder, such as diamond dust. This is accomplished by means of a small hammer, the dust beingscatter'ed over the edge of the cylinder and pounded into the relatively soft metal by means of the hammer; A cutter so charged with an abrasive. powder will serve to'cut a number of holes without rechargingthe edge with the diamond dust.

' After the edge becomes ineffective as a cutter, it can bgecharged. The action 'of this annular cuttin dviceis such that b the time the indmg wheels have finished the edge of t e blank, t-he annular cutter has cut its way through the glass. In operation the cylinder cuts by reason of its weight, settling down into the glass as it cuts, this being permitted by reason of the mounting a of the axle or spindle 32' to move freely in the supporting bar 31. The universal mounting by use of the ball and socket joint permitsv the cutter to adjust itself to the groove cut and avoids any tendency to bind. I The action of the cutter isra-pid and clean 3 and the walls of the hole which is out are" smooth and straight and not tapered as isthe case wherecarborundum cutting-is emr ployed. 'Thecylinder has been employed in-cutting openings as-highas 13" in diameter and the metal cylinder employed in such case ispreferably about 2' high and What I claim is i- 1. In combination 1n apparatus 61 finishing circular glass blanks, atable or support, means for securing the blank to be finished to such table or support, idler grindin wheels arranged around the periphery, o?

the table with their faces in position to engage the edge of thebl ank and atlvarying angles with respect "to said edge, a cutting cylinder with its axis concentric with that of the table or support with its lower edge engaging the glass and held a ainst rota-' tion, and "means for rotating t e table or' support to move the glass blank relative to the said wheels and cylinder and so secure a cutting-action thereon. T 2. In combination in apparatus for finishing circular glass blanks, a. table orsupport, means for securing the blank to be finished vices arranged around the periphery of the table or support, means causing such devices to press against the edge of the blank, an annular cutter with its axis concentric with the axis of the table or support engaging. the surface of the glass, and means for causingthe table and grinding devices and cutter to rotate relatively to'secure a cutting action between said grindin devices and annular cutter, and theglass blank.

In -testimony whereof, I have hereunto no to such table or support, idler grinding deenerated mymme t 1st day 

